Dropped grease filter

hello, i removed the two side by side grease filters to clean and when i tried to replace them one of them dropped down the opening into the area below. i tried to retrieve it but area is very narrow and deep. i can't see it at all or feel it when i stuck a stick in there to see how far down it is. when i opened cabinet below to try and retrieve from underneath, it is all enclosed in metal casing and there's no obvious opening or access panel. i left the telescoping downdraft in the up position because i'm concerned that if i try to close it the fallen filter will get in way or keep it from closing because of where it has fallen. i've never used one of these telescoping types before, it came with house we bought recently, and there is no owners manual. i called ge help line and they were no help and wanted to send a service call and also checked out online manual and it didn't say anything about this problem, at least as far as i could see. i hope you can help. can it be retrieved, either from above or below? did it fall into an area that will not affect closing of the telescoping section. is it just gone and i need to replace the lost filter? thanks for your help.